A lovely educational tale about how animals live in harmony and benefit their ecosystem through commensalism A family of beavers love their pond, which they've worked hard to turn from a bedraggled landscape into a thriving wetland. But when a family of otters move in and start reaping the rewards of the beavers' efforts, the only thing the beavers can do is tolerate their new neighbors as best they can. Despite the fact that the otters can be rather annoying, the two species eventually strike a balance, and in the process benefit the rich new ecosystem around them.